Errors occurring after upgrading to WordPress 4.6

[Pulsar_Media]

Hi,

I am facing several errors in the backend after upgrading to WordPress version 4.6

For example when i try to delete a theme i get the following error outlined in a red notification box:

Deletion failed: undefined

When i try to update a plugin i get the following error:

Update Failed: Internal Server Error

Is there a quick fix for this?

[hardeepasrani]

Hi,

It appears to be an issue with your WordPress installation or your server, not an issue with WordPress. With that being said, it should be a support ticket and you should open one here with all the details: ​https://wordpress.org/support/

[Pulsar_Media]

Looks like an issue with WordPress to me - everything was working perfectly fine until i upgraded to 4.6 and did the database upgrade. I upgraded 7 sites and they are all giving me these errors. I reinstalled WordPress on one of the sites and its working fine now - its definitely an issue with WordPress - or the database upgrade process.

[hardeepasrani]

Are all the sites on the same server? :)

[swissspidy]

With a topic in the support forums we could more easily help you and open a trac ticket if necessary.

When you open the developer console in your browser (F12), you should be able to see the Ajax requests triggered when deleting or installing a plugin/theme. If you could share the responses of those, this would be helpful.

I assume there are some PHP notices or errors being thrown which cause the process to fail.

[Pulsar_Media]

Ok here's one example - i just tried to delete one of my child themes and here is the WordPress error i got along with the ajax return message in the web console:

WordPress error:

Deletion failed: The requested theme does not exist.

Ajax message:

{"success":false,"data":{"delete":"theme","slug":"hope-charity-theme-child","errorMessage":"The requested
 theme does not exist."}}

The theme is installed and i can verify its installed through FTP - but for some reason WordPress thinks it doesn't exist.

[SergeyBiryukov]

Replying to Pulsar_Media:

The theme is installed and i can verify its installed through FTP - but for some reason WordPress thinks it doesn't exist.

Might be related to #37924.

[Pulsar_Media]

If i understand correctly that article mentions that the error is related to uppercase characters in the directory name? My theme does not contain uppercase characters in the main theme folder which is labelled "hope-charity-theme-child"

Sorry but i don't believe that article resolves anything.

[swissspidy]

#38058 was marked as a duplicate.

[charlesrodmell]

In case it helps anyone, I got the "Deletion failed: undefined" when trying to delete a theme. My host tweaked the firewall a bit and I was able to delete it. Not sure of the details.

[thesolver.us]

I ran into this error. For me, the solution was upping the PHP memory from the provider's default 64M:

memory_limit = 128M

[costdev]

This issue can be caused my permissions issues, an insufficient memory_limit value, other server configuration issues, and a myriad of other causes, it's best that any future instances of this issue are raised in ​the support forums for exploration.

If the issue is definitively linked to WordPress Core, this ticket can be reopened.

For now, as this hasn't been identified as an issue with WordPress Core, there has been no activity 5 years, and this was originally reported against WordPress 4.6, I'll close this ticket as worksforme, for lack of a better resolution to assign.